Need help ASAP

1.) List a few reasons why a beaver is an example of a keystone species.

2.) In architecture, a keystone is the
stone at the center of an arch that holds the arch together. How does this
definition relate to a keystone species?

If you were given a map of the sensory cortex in the postcentral gyrus of the cerebrum, do you think the map would have more “space” devoted to the regions of the body that have the highest density of sensory receptors, or the regions of the body that have the lowest density of sensory receptors? explain.